Generally, a fuel pump of a vehicle is mounted in a fuel tank of the vehicle and serves to suck a fuel and forward the fuel to a fuel injection device mounted in an engine.
In addition, the fuel pump of the vehicle is classified into a mechanical fuel pump and an electrical fuel pump, and a turbine type fuel pump 10, which is a kind of electrical fuel pump, is mainly used in an engine using gasoline as the fuel.
The turbine type fuel pump 10 is configured to include a driving motor 20 disposed in a motor housing 60 thereof, upper and lower casings 30 and 40 disposed at a lower end portion of the motor housing 60 and closely adhered to each other, and an impeller 50 disposed between the upper and lower casings 30 and 40, as shown in FIG. 1. In addition, the impeller 50 is coupled to a shaft 21 of the driving motor 20 to thereby be rotated together with the driving motor 20.
That is, as the impeller 50 is rotated, a pressure difference is generated, such that a fuel is sucked into the impeller 50, and pressure of the fuel rises by a rotational flow generated by continuous rotation of the impeller 50, such that the fuel is discharged.
Therefore, the fuel is introduced into a fuel inlet 41 of the lower casing 40 and then passes through the rotating impeller 50, such that pressure of the fuel is raised. Then, the fuel flows to a check valve 70 formed at an upper portion of the motor housing 60 along an inner portion of the motor housing 60 through a fuel outlet 31 of the upper casing 30 and is then supplied to a fuel injection device mounted in an engine of a vehicle.
Here, the impeller 50 includes several blades 51 formed in a disk shape in an outward direction of a circumferential surface thereof along the circumferential surface thereof and blade chambers 52 formed between the respective blades 51 so as to penetrate through both surfaces of the impeller 50 as shown in FIG. 2, and the fuel is introduced into the fuel inlet 41 of the lower casing 40, such that a rotational flow is generated in a space between the blade chamber 52 and a lower flow passage groove 42 formed in the lower casing 40 and an upper flow passage groove 32 formed in the upper casing 30 and a circulation process in which the fuel is introduced into a blade chamber 52 adjacent to the lower flow passage to generate the rotational flow is repeated to convert kinetic energy due to the rotation of the impeller 50 into pressure energy of the fuel, such that the fuel is delivered to the fuel outlet 31 of the upper casing 30, as shown in FIG. 3.
Further, the impeller 50 according to the prior art includes a circumference center guider 53 formed at the center of the circumferential surface thereof along the circumferential surface thereof, thereby making it possible to efficiently generate the rotational flow formed in a space between the blade chamber 52 and the lower flow passage groove 42 and the rotational flow formed in a space between the blade chamber 52 and the upper flow passage groove 32.
However, the fuel introduced into the fuel inlet flows along the lower flow passage groove 42 of the lower casing 40 and then flows the upper flow passage groove 32 of the upper casing 30 through the blade chamber 52 at an end of the lower flow passage groove 42. In this case, impact of a fluid is generated in the blade chamber 52 due to the fuel passing through the blade chamber 52, such that high frequency noise is generated.
As the prior art related to this, Korean Patent Laid-Open Publication No. 2012-0113332 entitled “Impeller for Fuel Pump of Vehicle” has been disclosed.